196 Bulletin Vanderhilt Marine Museum, Vol. V 



The chelipeds are characteristically very uneqiial in the male, in 

 large adults being two and one-half to three and one-half times the 

 length of the carapace. The merus is unequally trigonal, the postlat- 

 eral surface convex, terminating in an acute tooth at the distal angle, 

 from which point two carina-like margins diverge, one sharply defin- 

 ing the postlateral face and the other defining the anterolateral face of 

 the merus. A distinct constriction occurs dorsally between this tooth 

 and a distal tooth, from which a light carina runs transversely across 

 the postlateral face of the merus ; the carpus is convex, with its ante- 

 rior lateral margin finely granulose ; the hand, including the fingers, is 

 two to two and one-half times as long as the carapace, the palm being 

 as high as its proximal portion is long, with the outer surface moder- 

 ately rounded and coarsely granulose on the outer lower two-thirds, 

 finely so above ; the upper proximal border forms a distinct elbow ; the 

 lower margin of the palm is continuous with that of the lower finger, 

 moderately curved, very slightly sinuate and emphasized for the distal 

 three-fourths of its length by a flat carina defined above by coarse 

 punctae. On the inner surface of the palm there are two conspicuous 

 crests, the anterior of which is deeply grooved and nearly vertical, an- 

 teriorly becoming confluent with the cutting edge of the lower finger. 

 The second crest is even more conspicuous and is oblique, running 

 from midway the palm down to the lower border. The fixed finger is 

 distinctly compressed where it arises from the palm, and continues flat 

 throughout its length with the upper margin very sinuate, proximally 

 touching the opposite finger, thence very concave, followed by an en- 

 larged tooth near the tip, which causes the tip to have a notched-trun- 

 cate aspect. The entire cutting edge is regularly, finely dentate. Note- 

 worthy variations occur in the degree of development of the large sub- 

 distal tooth, which of course affect the notch-truncate aspect. In one 

 large male in the "Alva'^ series, this subdistal tooth is reduced and 

 the related truncate area is longer, the tip of the fixed finger extend- 

 ing about 2 mm. beyond that of the upper one. In all others the tips 

 of the fingers meet. The upper finger is also laterally compressed, 

 smooth, much more curved than the upper, acute tip, the cutting edge is 

 regularly dentate and has two or three longer teeth, subbasally, and 

 one larger tooth opposite the large tooth of the lower finger. The gape 

 between the fingers is a wide ellipse in the greater extent of its length, 

 abruptly, irregularly narrowed at either end. 



The small cheliped of the male is greatly reduced, laterally com- 

 pressed ; the fingers incurved, spoon-shape-tipped with a curious, fun- 

 nel-like brush of bristles on the inner distal margin. 



